#include <stdio.h>
#include <string.h>


int erfen(int *arr);
int main(int argc, const char *argv[])
{
	int arr[10]={9,19,25,31,49,52,60,71,82,93};

	int ret=erfen(arr);
	if(ret==1)
	{
		printf("yes\n");
	}

	return 0;
}

int erfen(int *arr)
{
	printf("plz input num\n");
	printf(">>>");
	int mynum=0;
	scanf("%d",&mynum);
	int a=0;
	int b=9;
	int flag=0;
	int mid=(a+b)/2;

	while(mynum>=arr[a]&&mynum<=arr[b])
	{
		if(mynum==arr[a]||mynum==arr[b]||mynum==arr[mid])
		{
			flag=1;
			break;
		}
		else
		{
			if(mynum>=arr[mid])
			{
				a=mid;
				mid=(a+b)/2;
			}
			else
			{
				b=mid;
				mid=(a+b)/2;
			}

		}
		if(a+1==b&&mynum!=arr[a]&&mynum!=arr[b])
		{
			break;
		}

	}

	return flag;

}
